
Quick answer — Keiichi Hirokawa worked on The Many Sides of Voice Actor Radio (Music), GARO -VANISHING LINE- (Music), Ultimate Otaku Teacher (Insert Song Composition) and 2 more anime.
Keiichi Hirokawa worked on The Many Sides of Voice Actor Radio (Music), GARO -VANISHING LINE- (Music), Ultimate Otaku Teacher (Insert Song Composition), Liar, Liar (Music), KamiErabi GOD.app (Music).